We have been given that at the restaurant, the cost of the meal before tax was $40. The tax is 8.5%. The cost after tax would be \$40+(8.5)/(100)* \$40. \$40+0.085* \$40 \$40+\$3.4 \$43.4 Sheri wants to leave at least an 18% tip. The cost of meal after tip would be \$43.4+(18)/(100)* \$43.4. \$43.4+0.18* \$43.4 \$43.4+\$7.812 \$51.212\approx \$51.2 Therefore, the total cost of the dinner would be $51.2.